Project Summary Chronic obstructive pulmonary disease (COPD) is a progressive disease affecting approximately fifteen million people in the US. COPD prevalence and morbidity is increased in individuals from low income households. Our research group has shown that indoor air pollutant concentrations (particulate matter (PM) and nitrogen dioxide (NO2)) are higher in lower income homes compared to higher income homes. In addition, increased pollutant concentrations in homes of former smokers with COPD are associated with respiratory morbidity, including increased respiratory symptoms, worse quality of life and increased risk of exacerbations and health care utilization. Though there are several factors that coalesce in poor environments that contribute to COPD morbidity or increase susceptibility to pollution exposure we will focus on obesity and dietary intake because: 1) the literature and our preliminary data strongly support the role of obesity and poor diet in contributing to COPD outcomes and susceptibility to air pollution, 2) both factors are prevalent in low-income urban settings therefore positive results are likely to have great potential for significant public health impact, 3) at the individual level, indoor air, diet and obesity are modifiable, unlike other factors such as outdoor air or access to healthcare, and 4) the hypotheses being tested in this application are highly novel. Obesity is traditionally defined by BMI alone, however, the phenotype of obesity as a disease is complex and heterogeneous and it is increasingly recognized that BMI is an imprecise measure of body composition. Given the importance of understanding these highly prevalent susceptibility factors for adverse COPD outcomes, we will use skin fold thickness and DEXA scanning, considered the ?gold standard? for the assessment of adiposity, in order to determine whether we can improve our ability to identify susceptible individuals, compared to the use of BMI alone. In addition, we will assess dietary patterns by food frequency questionnaire (FFQ) and assessment of serum vitamin and anti-oxidant levels in an observational study of 120 former smokers with moderate to severe COPD from a catchment area in Baltimore with a high proportion of low-income households. We aim to determine whether elevated fat mass and body composition (ie. higher trunk to total fat ratio) increases susceptibility to indoor pollution in low-income adults with COPD (Specific Aim #1); and whether adverse dietary patterns (Specific Aim #2a) and vitamin or nutrient antioxidant levels (Specific Aim #2b) lead to heightened susceptibility to indoor air pollution contributing to adverse health outcomes in COPD. Our study aims build upon a well-established infrastructure of investigators with complementary areas of expertise. Our study findings may identify several potential intervention strategies to reduce the harmful effects of PM and NO2 exposure in adults with COPD in low income populations. With COPD being the third leading cause of death in the US, developing strategies to reduce morbidity is an important public health priority.